Filesystem MCP Server

import { promises as fs } from 'fs'; import path from 'path'; import os from 'os'; import { normalizePath } from './utils/path-utils.js'; import { logger } from './logger.js'; /** * Converts a root URI to a normalized directory path with basic security validation. * @param rootUri - File URI (file://...) or plain directory path * @returns Promise resolving to validated path or null if invalid */ async function parseRootUri(rootUri) { try { const rawPath = rootUri.startsWith('file://') ? rootUri.slice(7) : rootUri; const expandedPath = rawPath.startsWith('~/') || rawPath === '~' ? path.join(os.homedir(), rawPath.slice(1)) : rawPath; const absolutePath = path.resolve(expandedPath); const resolvedPath = await fs.realpath(absolutePath); return normalizePath(resolvedPath); } catch { return null; // Path doesn't exist or other error } } /** * Formats error message for directory validation failures. * @param dir - Directory path that failed validation * @param error - Error that occurred during validation * @param reason - Specific reason for failure * @returns Formatted error message */ function formatDirectoryError(dir, error, reason) { if (reason) { return `Skipping ${reason}: ${dir}`; } const message = error instanceof Error ? error.message : String(error); return `Skipping invalid directory: ${dir} due to error: ${message}`; } /** * Resolves requested root directories from MCP root specifications. * * Converts root URI specifications (file:// URIs or plain paths) into normalized * directory paths, validating that each path exists and is a directory. * Includes symlink resolution for security. * * @param requestedRoots - Array of root specifications with URI and optional name * @returns Promise resolving to array of validated directory paths */ export async function getValidRootDirectories(requestedRoots) { const validatedDirectories = []; for (const requestedRoot of requestedRoots) { const resolvedPath = await parseRootUri(requestedRoot.uri); if (!resolvedPath) { logger.error(formatDirectoryError(requestedRoot.uri, undefined, 'invalid path or inaccessible')); continue; } try { const stats = await fs.stat(resolvedPath); if (stats.isDirectory()) { validatedDirectories.push(resolvedPath); } else { logger.error(formatDirectoryError(resolvedPath, undefined, 'non-directory root')); } } catch (error) { logger.error(formatDirectoryError(resolvedPath, error)); } } return validatedDirectories; }